Curved Detector Membrane Mounting for Low-Strain Focal Plane Conformity

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Solution Overview

Problem

Conventional infrared imaging cameras are bulky due to complex optics required to flatten their focal plane, and existing methods for curving detector arrays impose high stresses, limiting the degree of curvature.

Innovation Solution

A detector array with a semiconductor sensor and readout circuit, where the detector membrane is formed with a curved surface conforming to a focal plane, reducing strain through distributed force application and adhesion, allowing increased curvature and integration with a mount to sustain strain, using methods such as magnetic fields, fluidic channels, or piezo electric actuators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional pneumatic forming or direct contact molding methods are used to curve detector membranes, then the detector array can be curved, but high stresses are imposed on the detector array which limits the degree of curvature

Engineering Contradiction:

Improvecurvature of detector arrayVSAvoidstrain on detector membrane

Core Design Contradiction:

ShapeVSStress or pressure

Solution Approach 1:

A compliant mount made of elastomeric material serves as an intermediary between the detector membrane and the curved focal plane. This compliant material gradually conforms the detector membrane to the curved surface through adhesion, distributing strain across the entire curved surface rather than concentrating it at specific points. The mount acts as a buffer that allows curvature to be achieved without imposing high stresses on the fragile detector membrane.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the mechanical parameters of the mounting system by using a compliant, elastomeric material with appropriate durometer hardness (e.g., 30-70 Shore A). This material property selection allows the mount to be sufficiently rigid to maintain the curved shape while being compliant enough to gradually conform the detector membrane without causing excessive strain. The gradual attachment process also changes the temporal parameter of strain application.

Inventive Principle:

Principle #35Parameter changes

2Shape

If the detector membrane is made thinner to reduce strain, then the degree of curvature can be increased, but the detector membrane becomes more fragile and difficult to manufacture

Engineering Contradiction:

Improveradius of curvatureVSAvoidmanufacturing of thin detector membrane

Core Design Contradiction:

ShapeVSEase of manufacture

Solution Approach 1:

The compliant mount provides beforehand cushioning and support to the thin detector membrane during the curving process and operation. By having the elastomeric material in place before final attachment, the membrane is supported throughout the conforming process, preventing damage that would occur if the membrane were handled or curved without such cushioning. This allows thinner membranes to be used safely.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Shape

If complex optics are used to flatten the focal plane, then the imaging system can use a flat detector array, but the camera becomes bulky

Engineering Contradiction:

Improveflatness of focal planeVSAvoidbulk of optical components

Core Design Contradiction:

ShapeVSWeight of stationary object

Solution Approach 1:

Instead of using complex optics to flatten a curved focal plane onto a flat detector, the invention inverts the approach by curving the detector membrane to match the naturally curved focal plane of simple optics. This eliminates the need for bulky flattening optics while maintaining image quality. The compliant mount enables this inversion by making curvature feasible without excessive strain.

Inventive Principle:

Principle #13The other way round (Inversion)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables the creation of compact, high-curvature detector arrays that reduce optical component bulk, enhance field of view, and minimize aberrations, suitable for applications like wearable IR imagers and space exploration.

Implementation Method 1

applying one or more forces at a plurality of locations on the detector membrane and in one or more directions, the one or more forces deforming the detector membrane so as to form a curved surface

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

using methods such as magnetic fields, fluidic channels, or piezo electric actuators

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

fluidic channels

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Implementation Method 4

an adhesion between the mount and the detector membrane distributes the strain

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS12087803B2Imaging in curved arrays: methods to produce free-formed curved detectors

Publication Date: 2024.09.10 CALIFORNIA INST OF TECH

AI summary

A detector including a detector membrane comprising a semiconductor sensor and a readout circuit, the detector membrane having a thickness of 100 micrometers or less and a curved surface conformed to a curved focal plane of an optical system imaging electromagnetic radiation onto the curved surface; and a mount attached to a backside of the detector membrane. A maximum of the strain experienced by the detector membrane is reduced by distribution of the strain induced by formation of the curved surface across all of the curved surface of the detector membrane, thereby allowing an increased radius of curvature of the curved surface as compared to without the distribution.